Preliminary crystallographic data for cytochromes c' of Rhodopseudomonas capsulata and Rhodospirillum molischianum.

Crystallization conditions and unit cell parameters are reported for cytochromes c′ of Rhodopseudomonas capsulata and Rhodospirillum molischianum. While both proteins naturally occur as dimers having identical subunits of M_r ~ 14,000, R. capsulata was found to crystallize in the hexagonal space group P6₂ (or its enantiomorph P6₄) with one subunit per crystallographic asymmetric unit. This result suggests that the subunits of this molecule are related by exact 2-fold symmetry.